Screw-thread gage



(No Model.)

L. S. STA-BRETT.

SCREW THREAD GAGE.

No. 318,051. Patented May 19, 1885.

L y I J m I UNITED STATES PATENT OFFICE.

LAROY SUNDERLAND STARRETT, OF ATHOL, MASSACHUSETTS.

SCREW-THREAD GAGE.

SPECIFICATION forming part of Letters Patent No. 318,051, dated May 19, 1885.

Application filed September 5, 1883. (No model.)

To aZZ whom it may concern.-

Be it known that I, LAROY SUNDERLAND STARRETT, of Athol, in the county of Worcester, of the Commonwealth of Massachusetts, have invented ajnew and useful Improvement in Screw-Thread Gages; and I do hereby declare the same to be described in the following specification and represented in the accompanying drawings, of which Figure 1 is a side elevation, and Fig. 2 an edge View, of a screw-thread gage embodying my invention, the nature of which is defined in the claim hereinafter presented. Fig. 3 is a side View of one of the blades of such gage.

The improvement relates to screw-thread gages each of which consists of a handle and one or two series of blades pivoted to such handle, so as to turn into or out of it, as do the blades of a surgeons lancet, such blades as heretofore constructed having the screwthread gage teeth on their extreme ends. With blades so made it often becomes difficult if not impossible to gage a ferrule-screw, as for such purpose the blade has to be turned into a right angle with the handle, and as a consequence both blade and handle must be inserted in the aperture of the screw, which cannot be done when the aperture has a diameter less than thelength of the blade. WVith my improvement the blade only need be inserted endwise within the said aperture, which can be effected so long as the diameter of the aperture is greater than the width of the blade.

In the drawings, A denotes the handle, consisting of two metallic strips, a a, arranged side by side at a suitable distance apart and connected together and to two sets of blades, B, by rivets 12, going through them near their ends, all being as represented. Each of such blades has its series of gage-screw teeth formed on one side edge of it, as shown at c, and, besides, each blade at the inner end of such series has a terminal notch, 11, made in it, as shown, in order to allow play of the series of teeth in a screw lengthwise thereof while such screw is being revolved. Furthermore, the blade at its opposite edge is notched, as shown at e, to reduce it in width in parallelism with its series of teeth. The blades so made can all be turned or folded within the handle, and each may be turned out therefrom into line with it, as occasion may require. To facilitate the outward movement of the blades the handleis notched, as shown at f f. By reducing the blade at the back at e, the threaded portion is much reduced without weakening the portion at the eye. Thus the blade can be used for a small female screw, and is not weakened where it is held in the handle. By making the notch d on the toothedge at the end of the series of teeth exactitude is obtained in gaging. The ends of screw are finished or cut off without having the pitch of the threads; hence, when a gage is applied the teeth of the gage bearing. on such end prevents such gage from fitting snugly in the threads of the screw, and a miss will be made. With my device the notch d comes at the end of the screw, such end coming into the notch, allowingthe teeth of the gage to fit snugly 0n the thread of the screw. l

I do not claim a screw-thread gage composed of a handle and one or two series of blades arranged and pivoted therein and having each of such blades provided with a set of screw gage teeth extended along its outer end; but

I claim- The screw-thread gage, substantially as described, the same consisting of the handle A, made of two metallic strips, a a, side by side, and having the notchesf at opposite sides at the ends, and the two series of blades B B, one series hinged at each end of the handle A, such blades having the teeth 0 on one edge and notched at e at the back, forming a reduced or narrowed portion where the teeth are, and having the notch d at the inner end of the teeth, all constructed and arranged as and for the purpose set forth.

ANDREW J. HAMILTON, EMMA L. HAMILTON. 

